Please take a look at this tutorial that we have created (Link Below). All these walls that you are asking for are very easy to create and after watching this tutorial you will understand how to create them.
Link - https://www.youtube.com/watch?v=-fljeOK ... mHmpL9yedP
No not every material needs a texture, You could just simply use a colour.
Watch the video above and you will learn how to use your own textures and create your own library.
Drag and drop works 100% when using Google Chrome. only the latest version of Internet explorer will allow you to use Drag and Drop.
Mac will never allow you to use Drag and Drop no matter what browser you are using. Only in certain instances has users been able to drag and drop on a MAC.
Instead of drag and dropping you can go back into SketchUp and go to the PlusSpec Toolbar and select the 'SYNC' tool. This will download your materials that you have created.